Question

Using VSEPR theory, predict the probable structure of \[\ce{SO^{2-}_3}\].

Answer 1

1. The central atom is sulphur (S) bonded to three oxygen atoms.
2. Sulphur has one lone pair of electrons.
3. Electron groups around S = 4 (3 bond pairs + 1 lone pair).
4. According to VSEPR, the shape is trigonal pyramidal.
5. The bond angle is slightly less than 109.5° due to lone pair repulsion.
6. The ion has (sp³) hybridisation.

Thus, (\[\ce{SO^{2-}_3}\]) has a trigonal pyramidal shape with one lone pair on sulphur.